Method and device for producing a toothbrush by the two-component or multi-component injection-molding process

ABSTRACT

The invention relates to a method and a device for producing a toothbrush or part thereof by the two-component or multi-component injection-molding process. To produce in the brush body segments that are isolated from the rest of the brush body, a mold which comprises three hollow regions is used. Two of these hollow regions that are separate from one another serve for producing the segments and the other regions of the toothbrush from a first component. A third hollow region serves for distributing material to the segments that are isolated from one another and from the other regions, or the corresponding hollow region. The material remaining behind there is removed and sent for disposal. In a further step, connecting elements between the segments and/or the other regions are injection-molded from a second component.

This is a Continuation of application Ser. No. 11/632,042 filed Jan. 10,2007, which in turn is a National Stage of PCT Application No.PCT/CH2005/000398, filed Jan. 19, 2006. The disclosures of the priorapplications are hereby incorporated by reference herein in theirentirety.

BACKGROUND

The invention relates to a method and a device for producing atoothbrush or part thereof by the two-component or multi-componentinjection-molding process. The invention also relates to a toothbrush.

The production of toothbrushes by the two-component injection-moldingprocess is known per se and is used in particular in the case ofhigh-quality toothbrushes, to allow high requirements for function anddesign to be met. Widely encountered for example are toothbrushescomprising a body made up of a hard form-determining component, moldedonto which are the additional flexible functional elements, for examplea damping region in the neck region, cleaning elements in the headregion or a gripping zone in the handle region. The use of differenthard materials makes it possible for example to design the brush in twoor more colors and/or to choose different grades of material for thedifferent regions of the brush. Toothbrushes of this type are producedin a two-component injection-molding tool, in which all regions of thefirst component are first molded in a first mold from a first injectionpoint and then all regions of the second component are molded in asecond mold from further injection points. In the case of the knownmethods, the regions of the first component are completely contiguous,which facilitates both the actual injection-molding and the furtherhandling of the blank, in particular the transfer into the second moldcavity. A disadvantage of this is that it imposes limits on the formingof functional regions. For example, in the case of known toothbrusheswith a damping region in the neck, a meandering “framework” of hardmaterial is always present in the neck, connecting the handle region andthe head region to one another.

EP-A 0 923 326 or WO 98/27847 disclose toothbrushes which comprise twocomponents, a hard component and a soft component, the first componenthaving regions which are completely separate from the other regions ofthe first component and only connected to them by means of the secondcomponent. These isolated regions are referred to hereafter as“segments”. “Other regions” refers to those regions of the body thatcomprise the first component, are connected to one another and are not“segments”.

In the case of the toothbrush according to EP-A 0 923 326, individualbristle clusters are embedded in sleeve-like segments of a hardmaterial. The segments in turn are embedded in a flexible material,which forms the head part of the brush. The handle region and the neckregion in turn consist of the hard material. The production method isnot specified.

In the case of the toothbrush according to WO 98/27847, the head regioncomprises a number of segments, for example three or five, of a hardcomponent, which respectively carry a plurality of bristle clusters. Theintermediate spaces between the segments are filled with a softmaterial. Here, too, the production method is not specified.

The injection-molding particularly of small isolated structures from anumber of injection points is problematical for spatial reasons. WO99/16604 discloses a method in which a toothbrush with isolated segmentsused for securing bristle clusters is created from a single injectionpoint. A first mold is used for production, a mold which hasinterconnected cavities for forming both the segments and the otherregions. The segments are separated from one another by movable moldcores, but not completely. This is so because the mold cores haveclearances, through which the liquid material can flow from onepart-cavity into the neighboring part-cavity. After solidifying, webportions which connect the segments to one another and to the otherregions are formed in these clearances. Before the injection-molding ofthe second component, the mold cores are pulled out and the web portionsare consequently sheared off. Here it is problematical that the firstcomponent is distributed among the multiplicity of segments, since thematerial must in this case flow equally through a number of narrowclearances in the mold cores. Furthermore, although the connectionbetween two segments is interrupted by the pulling out of the moldcores, full mobility of the segments in relation to one another is notproduced. The remains of the web portions, which are only sheared offbut not removed, may impair the movement of the segments in anundefinable way. The injection-molding tool is also relativelycomplicated because of the movable mold cores. Because of the moldcores, there is a certain minimum distance between the segments.

SUMMARY

The invention is therefore based on the object of providing a method forproducing a toothbrush or part thereof by the two-component ormulti-component injection-molding process by which a toothbrush or partthereof can be produced with at least one segment in a simple way withgreat freedom of design with respect to the dimensions and position ofthe segment. Furthermore, a device for carrying out the method and atoothbrush with advantageous properties are to be provided.

In a variant of the invention, a large part of the brush body, forexample the entire form-determining part, is produced from the firstcomponent, and the segments are isolated therefrom in the head region ofthe toothbrush. The brush handle region and neck region and any partsconnected thereto in the head region are then to be identified as the“other regions” of the toothbrush. In another variant of the invention,only part of the toothbrush, in particular a carrier element forbristles that is later to be connected to a separately produced brushbody, is produced, in that segments and other regions are formed fromthe first component and subsequently connected by means of the secondcomponent. The other regions are in this case for example thoselocations at which the carrier element is connected to the brush body,and the segments mainly mainly serve, as in the case of the firstvariant, for anchoring the cleaning elements, for example bristles. Theparts serving for anchoring the cleaning elements are referred tohereafter in connection with the carrier element as “segments” and theparts assigned to the brush body are referred to as “other regions”;however, this assignment is not obligatory.

The bristles may be attached by conventional tufting, by the Anchor FreeTufting (AFT) method or by the In Mold Tufting (IMT) method. Inconventional tufting, the segments preferably form sleeve-shapedreceptacles, into which the anchor plates are punched after theinjection of the two components. In the AFT method, the segmentspreferably have continuous holes, through which bristles are led,likewise after the injection of the two components, and are melted attheir rear ends for connection to the carrier element. In the IMTmethod, the bristles are molded into the segments during the injectionof the first component or are connected to them during the injection ofthe second component.

The carrier element is undetachably or detachably connected to the brushbody, the latter for example for the production of an exchangeable-headtoothbrush. Because of the good accessibility to the rear side,separately produced carrier elements are suitable in particular forproviding bristles by means of the AFT method, but conventional tuftingis also possible.

In an advantageous development of the invention, a first mold which hasat least three hollow regions is used for producing the first component.Two hollow regions that are completely separate from one anothercorrespond to the segments and the other regions of the brush body,respectively. A third hollow region serves the purpose of distributingthe liquid first component fed to it to the second hollow region,corresponding to the segments. If there are a number of segments, thesecond hollow region comprises a corresponding number of subregions,which are in connection with one another exclusively via the thirdhollow region. The cross section of the connecting locations ispreferably so small that the material remaining behind in the thirdhollow region (sprue and runner system) can be easily detached, forexample by moving away the corresponding part-mold. This material issubsequently sent for disposal, preferably recycled. Therefore, bycontrast with the use of a number of injection points, the third hollowregion makes it possible for material to be distributed from oneinjection point also to structures that are many times smaller inrelation to the brush body. It is consequently possible for example toproduce fine sleeves that are isolated from one another for securingbristle clusters. The segments are completely separate from one anotherafter removal of the material from the third hollow region, and cantherefore also move with respect to one another without impairment afterbeing encapsulated with the second component.

In principle, the hollow regions of the entire first mold may besupplied through a single injection point, if there is a connectionbetween the first hollow region and the third hollow region. It ispreferred that the first and third hollow regions are respectivelysupplied from at least one injection point of their own.

Depending on the number and position of the segments, the third hollowregion may also be subdivided into subregions that are separate from oneanother, which are supplied by one injection point in each case.

In an advantageous development of the method, the spatial position ofthe segments in relation to one another and/or to the other regions ischanged before the second component is injected. This is possiblewithout any problem on account of the complete separation of thesegments from one another and from the other regions. The segments mayalso be arranged such that they are touching one another and/or theother regions and/or are engaging/mounted in one another before theinjection of the second component.

The first component is preferably a hard component and the secondcomponent a hard or soft component. Styrene-acrylonitrile (SAN),polyethylene terephthalate (PET), polyethylene (PE),polymethylmethacrylate (PMMA), acrylobutadiene styrene (ABS) orpolypropylene (PP) is used for example as the hard component. Arubber-elastic material, preferably a thermoplastic elastomer (TPE), orfor example polyurethane (PU), is used as the soft component. Thehard-hard combination of materials, for example the combination of atransparent hard material with an opaque hard material and/or a hardmaterial of different colors, is considered to be possible. Thehard-soft combination is preferred however for the production offlexible connecting elements between the segments. The injection offurther components is likewise possible. These are preferably furthersoft components, which are injection-molded onto the segments or ontothe other regions.

The method according to the invention is used with preference to producea toothbrush which has a plurality of segments in the head region. Inthe head region, a membrane of the second component, in which thesegments are embedded, is mounted as a connecting element between thesegments and the remaining body. The connection of the membrane to thebrush body may be direct or obtained by being embedded in a carrierelement which is connected to a separately produced brush body. Thesegments are with preference in the form of sleeves or cups and canrespectively hold one or more bristle clusters attached conventionallyor by the AFT method. The membrane provides particularly flexiblemounting of the bristles.

In particular in the case of a flexible carrier element which isprovided with bristles by the AFT method, in particular one producedaccording to the invention, there is the problem that the bristle meltdoes not adequately adhere to the carrier element. In this respect, itis proposed to treat the bristles or the carrier element before themelting of the bristle ends in such a way that increased adhesionbetween the carrier element and the bristles is produced by the melting.

BRIEF DESCRIPTION OF DRAWINGS

Examples of the invention are described below and are represented in thedrawings, in which, purely schematically:

FIG. 1 shows a sectional view of a first injection mold with threepart-molds after the injection of a first component;

FIG. 2 shows a sectional view according to FIG. 1 after the separationof the first part-mold from the second and third part-molds;

FIG. 3 shows a sectional view according to FIG. 1 after the separationof the second and third part-molds;

FIG. 4 shows a sectional view of a second injection mold with twopart-molds after the injection of a second component;

FIG. 5 shows a sectional view according to FIG. 4 after the separationof the two part-molds;

FIGS. 6 a, 6 b, 7 a, 7 b show various views of a brush head produced bythe method according to the invention;

FIG. 8 shows a two-component injection-molding tool according to FIGS.1-5;

FIGS. 9, 10 show views of a further toothbrush after the injection ofthe first component and second component, respectively;

FIGS. 11-15 show examples of toothbrushes with a carrier element,separately produced by the method according to the invention, forbristles with a membrane in various views;

FIGS. 16, 17 show examples of toothbrushes which have a membrane in thehead region, with a brush body produced by the method according to theinvention;

FIG. 18 shows in a greatly simplified form a first injection-moldingcycle in which two parts of a toothbrush are produced;

FIG. 19 shows in a plan view the two parts produced in the firstinjection-molding cycle;

FIG. 20 shows the encapsulation of the joined-together parts accordingto FIG. 19 by means of a soft component;

FIG. 21 shows in plan view the toothbrush without bristles, producedfrom the parts according to FIG. 19 by the method according to FIGS. 18and 20;

shows in plan view a first part produced by injection-molding;

FIG. 23 shows in plan view a second part produced by injection-molding;

FIG. 24 a shows in plan view a view of a further toothbrush with theparts that are shown in FIGS. 22 and 23, which are connected to oneanother by means of a further component, in particular a soft component;

FIG. 24 b shows in side view the toothbrush that is shown in FIG. 24 a;

FIG. 25 shows a longitudinal sectional view of a further injection moldwith two hollow regions for producing the two toothbrush parts that areshown in FIGS. 22 and 23; and

FIG. 26 shows a cross-sectional view of the injection mold that is shownin FIG. 25 through the plane

DETAILED DESCRIPTION

FIGS. 1-5 show views of an injection-molding tool used for carrying outthe method according to the invention in various stages of the method.FIG. 8 shows this tool in an overview. The aim is to produce atoothbrush with bristle clusters flexibly secured in sleeves, forexample according to claim 24 or according to EP-A 0 923 326.

A first mold 10, represented in FIGS. 1-3, is made up of threepart-molds 30, 32, 34, which may in each case be subdivided further.Between the first part-mold 30 and the second part-mold 32, both firsthollow regions 12 are formed by wall regions 12 a, 12 b (see FIG. 2) andsecond hollow regions 14 are formed by wall regions 14 a, 14 b (see FIG.2). The first and second hollow regions 12, 14 are not in connectionwith one another. The second hollow region 14 is subdivided into anumber of subregions, which are likewise not directly in connection withone another. Between the second part-mold 32 and the third part-mold 34there is a third hollow region 16, which is formed by wall regions 16 a,16 b of the respective part-molds 32, 34 (cf. FIG. 3). This hollowregion is in connection with the subregions of the second hollow region14 by means of a number of arms 66. The arms 66 run conically and have alength of between 5 and 22 mm, preferably 17 mm. The connection of thearms 66 to the subregions is realized by means of narrowthrough-openings 28, which preferably have a round cross section with adiameter of 0.2-1.0 mm, with particular preference approximately 0.7 mm.If segments 20 produced in second hollow regions 14 have to receive anumber of bristle clusters 58, it is proposed for reasons of stabilityto connect each of the corresponding part-sleeves to the third hollowregion 16 by a single arm 66.

The first hollow region 12 is supplied with molten first component 38,preferably a hard component in the hot runner feed system, via a firstinjection point 24 (see FIG. 8), in order to produce the other regions18 of the toothbrush consisting of the first component, with theexception of the segments 20. As represented in FIGS. 6 a,b, 7 a,b, theother regions 18 are an all-round periphery 52 a of the head region 52with preformed sleeves 52 b for receiving bristles and parts of the neckregion 54 and of the handle region 56 (see FIG. 8). A hot runner nozzlewith a needle valve is preferably used for the first and third hollowregions.

The second hollow regions 14 are supplied with molten first component 38indirectly by a material supply at the third hollow region 16 via asecond injection point 26. Since solidified material 22 remains behindin the third hollow region 16, this is a case of material supply via acold runner.

In spite of a number of injection points 24, 26, the first component 38is preferably supplied by means of the same plasticizing unit, possiblyby the cascade method. There is suitable control for the opening andclosing of the material supply to the first and third hollow regions attimes coordinated with one another.

As represented in FIG. 2, the first and second part-molds 30, 32 areseparated from one another after the first component 38 isinjection-molded and left to solidify. The second and third part-molds32, 34 are separated simultaneously or preferably with a slight delay,cf. FIG. 3. The separating of the first and second part-molds 30, 32 hasthe effect that the solidified material 22 contained in the third hollowregion 16 is torn off from the segments 20 which have been formed in thesecond hollow regions 14. This tearing-off can be carried out in awell-defined manner and with low expenditure of force on account of thesmall through-openings 28. Remaining behind in the first part-mold 30are the other regions 18 and segments 20 separated from them and fromone another. Here, these have the form of sleeves. The segments 20 may,however, also have the form of rings or cups, as explained furtherbelow. The sleeve-shaped segments 20 are fitted on pins 30 a, which arepart of the first part-mold 30 and serve for shaping the inner region ofthe sleeves or segments 20. The pins 30 a can preferably be displaced inrelation to a matrix 30 b, in order to adapt the position of the sleevesin the brush head as a unit. Furthermore, it is possible to freely movethe pins 30 a, and consequently the segments 20, by removing the matrix30 b after the injection of the first component 38 (not representedhere). This also allows the position of the segments 20 to be changed inrelation to one another and in relation to the other regions 18, withouta complicated holding and displacing mechanism for gripping and movingthe small segments 20 being necessary.

In a further method step, outlined in FIG. 3, the second and thirdpart-molds 32, 34 are also separated. The solidified material 22 isdetached by means of ram-like ejectors 36, which can be displaced intothe third hollow region 16, and is sent for disposal. The first mold 10is preferably arranged for this purpose in such a way that the ejectedmaterial 22 falls by gravitational force into regions in which there areno further molds, so that it cannot become caught in further moldcavities or on finished or half-finished products. The separation of thesprue and runner system consequently preferably takes place, seenspatially, in the lowest station/mold of the multi-station tool. Withpreference, the sprue and runner system is gripped from below by meansof a handling system or a robot and sent for disposal. This has theadvantage of ensuring that no sprue and runner systems can jam betweenthe platens.

In a further method step, the mold is changed. FIG. 4 shows the secondmold 40 for injecting the second component 39. It comprises twopart-molds, one of which is identical to the first part-mold 30 from theprevious steps. This has the advantage that, apart from applying a newfurther part-mold 46, no steps are necessary for separate gripping andmoving of the blank. The transfer into the second mold 40 preferablytakes place by rotating and/or displacing the first part-mold 30, forexample by rotation about an axis D through 180°, as shown in FIG. 8, orthrough 90°/120°, if additional polymer components are injected intofurther stations/molds. A manual mold change is also possible. The wallregions 48 a, 48 b (FIG. 5) of the further part-mold 46 are adapted inthe region of the fourth hollow region 48 to the form of the segments 20in such a way that there are merely thin connecting elements 42injection-molded between the segments 20. For this purpose, the wallregion 48 b has for example depressions 48 c, which substantiallycorrespond to the form of the segments 20, but are less deep. In thisway, the bottom 20 b of the segments 20 is covered during the injectionof the second component 39, while the upper periphery 20 a remains freeand is consequently surrounded by the second component 39. In order toensure a good connection between the segments 20 and the secondcomponent 39, apart from the sheet-like membrane 43 a thin materiallayer is also injection-molded around the upper periphery and theadjoining regions of the sleeve-shaped segments 20. The membrane 43preferably comes to lie as a collar around the segments 20. The segments20 are securely anchored by the consequently locally greater materialthickness of the membrane 43. The connecting elements 42 have altogetherthe form of a continuous membrane 43, in which the sleeve-shapedsegments 20 are embedded at their upper periphery 20 a, cf. FIGS. 6 b, 7a, 7 b. Furthermore, further regions 44 are injection-molded from thesecond component 39 at the neck and handle regions 54, 56. The moltensecond component 39 is supplied from the neck region 54 into the headregion 52 via a channel 62 cut out in the first component 38 (see FIG.3).

It is of course possible also to embed the segments 20 completely in thesecond component 39. This is preferably used if the segments 20 can bekept relatively thin. This is the case in particular when using the AFTor IMT method, in which the segments 20 are formed as rings that areopen at the bottom. This method is discussed in still more detail lateron.

For reasons of space, the injection point for the second component 39preferably does not lie on the membrane 43 in the head region 52, but inthe neck or handle region 54, 56. The displacement of the injectionpoint also allows the otherwise low material consumption to beartificially increased, in order to maintain a minimum shot weight.

FIG. 5 schematically shows a further method step, in which thepart-molds 30, 46 of the second mold 40 are separated from one anotherand the toothbrush body is removed.

FIG. 8 shows a two-component injection-molding tool according to FIGS.1-5 with two molds 10, 40, the left-hand first part-mold 30 of each ofwhich is identical. The part-molds 30 and 32/34 as well as 30 and 46 canbe separated along a vertical plane E or in the region of the toothbrushslightly offset in relation thereto. The left-hand first part-molds 30are also rotatable about the horizontally running axis of rotation D, inorder to transfer a product after production of the first component intothe second mold 40. When the first mold 10 is separated, the solidifiedmaterial 22 in the third hollow region 16 falls downward over a slopingsurface 64, and consequently cannot become caught in other products ormolds.

In FIGS. 6 a,b and 7 a,b, various views of a brush head produced by themethod according to the invention are represented. FIG. 6 a shows partof a toothbrush 50 in a view from below at the head part 52, i.e. at therear side facing away from the bristles. FIG. 6 b shows the sametoothbrush 50 in a view of the bristle-carrying front side of the headpart 52. FIGS. 7 a and b show the same brush in cross section andlongitudinal section along the lines I-I and II-II, respectively.

The bristle clusters 58, only one of which is outlined, are secured insleeve- or cup-like segments 20, which have preferably beenconventionally provided with bristles by tufting. Here, one segment 20holds one to three bristle clusters 58, but may also hold larger groupsof bristle clusters or other cleaning structures, such as for exampleflexible cleaning elements. The openings of the sleeves 20 areelliptically shaped, in order to adapt themselves to the form of theanchor plates during conventional tufting. That is to say that theanchor plates are respectively placed in such a way that they come tolie substantially on the major axis of the ellipse. By the fact that thesleeve-shaped segment 20 consequently comes to lie around the anchorplate, the load it takes to pull out the bristles is increased. In orderto make reliable tufting possible, the segments 20 are conically formedon the undersides 20 b. The bottoms of the underside 20 b preferably liein one plane, so that during tufting they can be supported on anunderlying surface. An underlying surface with a plurality of recessesinto which the segments 20 fit, and by which they are well supported andlaterally fixed during tufting, is preferably used. Although themembrane 43 may have a convex, arched basic form, the segments 20preferably have a flat upper bounding surface. As a result, theinserting and anchoring of the bristle clusters 58 is likewisefacilitated.

The connection of the sleeve-shaped segments 20 to the material 22 andthe connection of the corresponding hollow regions 14, 16 is preferablysuch that each segment 20 is centrally connected on its underside to thematerial 22. The third hollow region 16, or the first component 38present in it, acts as a distributing element during theinjection-molding. As a result, good material distribution, cleandetachment/tearing-off of the solidified material 22 and reduction ofcrack formation are made possible. The material connection preferablyhas a round cross section with a diameter of 0.2-1 mm, preferably 0.7mm.

Alternatively, the segments 20 may also be provided with bristles by theAnchor Free Tufting (AFT) or In Mold Tufting (IMT) method. In the caseof providing bristles by AFT, the segments 20 are preferably sleevesthat are open at both ends, into which bristle clusters 58 are inserted,preferably after the injection of both components 38, 39, and aresubsequently melted at their rear ends.

In particular in the case of the AFT method, initially only the carrierelements for the bristles, i.e. part of the bristle head, are producedby the method according to the invention. With preference, the carrierelements particularly comprise sleeve-shaped segments 20 that are openat both ends, connected by connecting elements in the form of apreferably thin membrane 43, which may also be perforated. The “otherregions” 18 made of the first component 38 may be small. They serve inparticular for the purpose of connecting, in particular welding, thecarrier element to a separately produced brush body to form a completetoothbrush 50. The “other regions” 18 may also serve the purpose oflending the carrier element the necessary stability, if the membrane 43does not have the necessary intrinsic stability, for example in that itis formed as an all-round or arcuate periphery or as two webs on whichor between which the membrane is mounted. The segments 20 are preferablyformed together with the other regions from a single injection point inthe hard component 38. The elements to be welded between the AFT carrierelement and the actual toothbrush body preferably consist of the samehard material, in order to increase the material compatibility andconsequently the durability of the weld seam. However, the main methodsteps for forming the segments 20 remain as already described. Examplesof such carrier elements and toothbrushes produced with them aredescribed further below with reference to FIGS. 11-15.

In the case of providing bristles by IMT, the bristle clusters 58 areinserted through suitable clearances into the first mold 10 alreadybefore the injection of the first component 38 and are encapsulated attheir rear ends with the first component 38 and in this way anchored inthe segments 20 or other regions 18. Fixing by the second component 39is also possible.

The segments 20 produced from the first component 38, a hard component,are located in the head region 52 of the toothbrush 50 and, in thisconfigurational variant, are surrounded by an all-round periphery 52 a,which likewise consists of the hard component. However, the segments 20are not connected to this periphery 52 a directly, but only via themembrane 43, acting as a connecting element 42, which consists of thesecond component 39, a soft component. Integrally formed with theperiphery 52 a are further sleeves 52 b, which likewise serve forsecuring bristles. The periphery 52 a together with the regions of theneck and handle regions 54, 56 that consist of the hard component formthe “other regions” 18, which are injection-molded in one operationtogether with the segments 20.

The membrane 43 is merely attached at the open end, to the upperperiphery 20 a of the segments 20 and to the upper side of the periphery52 a of the head part 52. In this way, very flexible mounting of thesegments 20 is obtained, making great mobility of the segments 20relative to one another and to the periphery 52 a possible. The bristlesof the toothbrush 50 produced in this way are particularly compliant andadaptable as a result of the mounting, making particularly gentle teethcleaning possible.

The rear side of the toothbrush 50 is covered by a cover element 60, sothat no remains can become lodged between the segments 20. This coverelement 60 preferably consists of a transparent or translucent hard orsoft material, so that the movable mounting is visible from the outsideand can be shown directly to the purchaser. For fastening the coverelement 60, the periphery 52 a of the head region 52 preferably has anall-round welding edge 52 d. The all-round frame of the front side thatis formed as a result forms the support for the waterproof welding ofthe cover element 60.

The segments 20 (individual sleeve) are preferably between 2 and 6 mm(with preference 3 mm) deep and between 2 and 4 mm (with preference 3mm) wide. The membrane 43 is preferably between 0.3 and 3 mm thick, withparticular preference between 0.6 and 1.0 mm. This allows the segments20 to perform a tumbling movement. The distance between the segments 20is preferably at least 0.2 and at most 3 mm. They preferably take up atleast half the surface of the membrane 43 or of the surface area definedby the periphery 52 a. Their bottoms 20 b are preferably kept at adistance from the cover element 60 of at least 1-3 mm.

The membrane 43 may be arched (convexly or concavely) or flat. The upperperipheries 20 a of the segments 20 preferably have a flat upperbounding surface, for better insertion and anchorage of the bristleclusters 58. The segments 20 are preferably laterally and/orhorizontally fixed for the insertion of the bristle clusters 58.

In the same production step, additional rubber-elastic cleaning ormassaging elements, which are integral with the membrane, may be formedfrom the same material as the membrane.

In an alternative embodiment (not represented), the connecting elements42 also extend over the entire height of the segments. A differentmobility of the segments 20 is obtained as a result. In this case it ispossible to dispense with a form-determining all-round periphery 52 a ofa hard component 38. It is also possible to connect the segments 20 notover their full surface area but only by thin webs of the hard or softcomponent. This produces head structures with openings between theindividual segments 20. The flexibility of the head can be specificallyinfluenced as a result.

FIG. 9 shows a further (not yet finished) toothbrush 50 produced by themethod according to the invention in longitudinal section after theinjection of the first component 38 of the body 50′. To produce thefirst component 38, a first mold is used, substantially formed as shownin FIGS. 1-3 and comprising three part-molds (not represented here). Thecontact surface between the second and third part-forms has in this casethe form of a plane and is designated by E.

In the case of the toothbrush 50 to be produced, individual segments 20are formed both in the handle region 56 and in the neck region 54. Thesegments 20 in the handle region 56 may have the form of bars running inthe transverse direction. The segments 20 in the neck region 54 arebar-like and in the finished state serve in conjunction with the softcomponent as an elastic bending zone. The second hollow regions 14 aretherefore divided into two groups, which are of a form complementing thesegments 20 in the handle region 56 and the neck region 54,respectively. The segments 20 in the handle region 56 are connected toone another by means of a first distributing element (solidifiedmaterial 22) of the first component 38, which is of a form complementingthe third hollow region 16. This region is supplied with the firstcomponent 38 via an injection point 26, so that material is directedinto the second hollow regions 14, solidifies there as segments 20 andin the third hollow region 16 solidifies as material 22. The segments 20in the neck region 54 are connected to one another by means of a furtherdistributing element (solidified material 22′) of the first component38, which corresponds to a further third hollow region 16′. This regionis supplied with the first component 38 via a further injection point26′.

In the case of the present example, the openings 28 between the secondand third hollow regions 14, 16 lie in the separating plane E. Thisfacilitates demolding, in particular the detachment of the thirdpart-mold and the distributing elements (22, 22′), and the production ofthe part-mold.

However, the position of the segments 20 in relation to one another andto the other regions of the first component 38 (part of the neck region54, head region 52) does not correspond to the desired final state. Inthe case of the finished body 50′, which is shown in section in FIG. 10,in the handle region 56 the gaps 70 between the segments 20 and theother regions are reduced and the distances between the segments 20 areincreased. Furthermore, some of these segments 20 and the segments 20 inthe neck region 54 have been displaced in the plane of the drawingperpendicularly in relation to the separating plane E, in order thattheir contours are adapted to the contour of the toothbrush 50 with aslightly curved body 50′.

The described relocation of the segments 20 in relation to the otherregions of the first component 38 takes place after the detachment ofthe distributing elements (22, 22′) when changing between the first mold10 and the second mold 40. A suitable handling unit is preferably used;the segments 20 may, however, also be simply allowed to fall intocorresponding clearances in the second mold.

FIG. 10 shows the finished body 50′ of the same toothbrush 50 afterrelocation of the segments 20 and after the injection of the secondcomponent 39. The second component 39, which is a soft component here,has the effect that the segments 20 are resiliently embedded and areconnected to the other regions of the first component 39 to form acontinuous body 50′. This is subsequently provided with bristles in thehead region 52 in a known way.

FIGS. 11-17 show further variants of toothbrushes 50 and carrierelements 68 for toothbrushes 50 which have been produced by the methodaccording to the invention. In the case of the examples from FIGS. 11a-e, FIGS. 12 a-e and FIGS. 13-15, carrier elements 68 are firstlyproduced by the method according to the invention, provided withbristles and subsequently connected to a separately produced body 50′.In the case of the examples from FIGS. 16 and 17, the entire brush body50′ is produced by the method according to the invention andsubsequently provided with bristles.

In the case of the examples from FIGS. 11 a-e, FIGS. 12 a-e and FIGS.13-15, in a first step a plurality of sleeve-shaped segments 20 and theother regions 18 of the carrier element 68 are produced from a firstcomponent 38, in particular a hard component. In a further step,connecting elements 42 in the form of a membrane 43 are molded on. Themembrane 43 is thinner in a direction perpendicular to the carrierelement 68 than the segments 20, which protrude from the membrane 43 onboth sides (see FIGS. 11 e, 12 e). The segments 20 may in principle beof any desired form, but are preferably in the form of sleeves or cupsand, perpendicularly in relation to the carrier element 68, are open atone or both ends. In the case of the conventional provision of bristlesby tufting, the cross-sectional area of the segment openings ispreferably elliptical, as shown on the left in FIG. 11 b. In the case ofthe conventional provision of bristles, segments 20 with openings at oneend are produced (for example as in FIGS. 7 a,b).

In the case of providing bristles by AFT, any other desiredcross-sectional openings may be realized, for example in the form of afigure of eight or a kidney shape, as shown in the middle and on theright in FIG. 11 b. The segments 20 have continuous channel-likeopenings 72, through which bristle clusters 58 can be led after theproduction of the carrier element 68. These are subsequently melted attheir rear ends, in order to anchor them on the carrier element 68.

In the example of FIGS. 11 a-e, the other regions 18 form an ellipticalclosed periphery 74 (similar to the all-round periphery 52 a), ontowhich further sleeves 76 (similar to the further sleeves 52 b) aredirectly molded. They serve like the segments 20 for fastening bristlesand are open at one or both ends. Within the periphery 74 there are anumber of segments 20 of different shapes and sizes. They are connectedto one another and to the periphery 74 by the membrane 43. The membrane43 is preferably elastic, so that elastic bristle anchorage is realized.

The carrier element 68 is subsequently provided with bristles 58conventionally or by means of AFT (FIG. 11 d).

A brush body 50′, which has the form of a spoon with a recess in thehead region 52 (FIG. 11 c), was produced in a separate operation. Formedin the head region 52, or at the periphery of the recess, is anall-round edge 78, against which an outer edge 80 of the carrier elementcomes to bear. The carrier element 68 and the body 50′ are undetachablyconnected to one another, preferably by welding, along the line 78/80(FIG. 11 e).

The welding area may be partially interrupted by openings or othermaterials, in particular soft materials. Variants in which anexchangeable-head toothbrush is realized by a detachable connection ofthe other regions 18 to the body 50′ are also advantageous.

In the example of FIGS. 12 a-e, in a first method step a plurality ofsleeve-shaped segments 20 and two straight, cross-sectionally L-shapedmaterial pieces 82 are produced from the first component 38, a hardcomponent (FIG. 12 a). The material pieces 82 may be identified as the“other regions” 18. The membrane 43 is injection-molded as a connectingelement 42 between the material pieces 82 and the segments 20 (FIG. 12b). The carrier element 68 produced in this way is subsequently providedwith bristles conventionally or by means of AFT (FIG. 12 c). Aseparately produced brush body 50′ is bent in the head region 52 to forma carrying structure and has two edges 78, running in the transversedirection and serving as anchoring locations for the carrier element 68,and consequently indirectly for the membrane 43. The elongate materialpieces 82 are fastened to these, preferably by means of welding. Theunderside 80′ of the material pieces 82 is thereby adapted to the edge78.

The previously planar carrier element 68 may be connected to the headregion 52 of the body 50′ under prestress, so that it arches up andcreates a cushion-like structure, by which the bristles 58 are mountedin a particularly resilient manner (FIGS. 12 d+e). The head region 52may be open at the sides, as shown in FIG. 12 d, or closed at the sides,in a way analogous to FIG. 11, but without a lateral weld seam. Thecarrier element 68 may also be bent already before insertion into thebody 50′, for example in that the membrane 43 is produced in acorrespondingly bent form or in that it is thermoplastically deformedduring or after being provided with bristles, for example by a bent AFTdie.

FIGS. 13, 14 and 15 show variants of the toothbrush 50 that is shown inFIG. 12. The brush body 50′ is bent in the head region 52, branched oneor more times toward the front end to form a skeletal carrying structureand has two, four or eleven plate-shaped anchoring locations 84, formedat the end of a branch. A further anchoring location 84 is formed, as inthe case of FIGS. 12 d+e, as an elongate edge 78 at the transition fromthe head region 52 to the neck region 54. The corresponding carrierelement 68 has, as in the case of FIGS. 12 b+c, an elongate materialpiece 82 at one end, and, distributed in a way corresponding to theanchoring locations 84, two, four or eleven plate-like material pieces82′, between which the membrane 43 is located. These may serveexclusively for anchoring the carrier element 68 to the brush body 50′(FIGS. 13+14) or additionally also themselves carry bristle clusters 58(FIG. 15). Depending on the arrangement of the anchoring locations 84and the material pieces 82, 82′, the membrane 43 is connected to thebody 50′ without stress, drawn in length or width or made to arch up.The more anchoring locations 84 there are, the more possibilities forvariation there are with regard to the form of the membrane, andconsequently the elastic properties of the bristle mounting. Theanchorage between the holding locations is preferably performed by meansof ultrasound. This allows edges of the carrier element 68 to engage ingrooves of the holding locations with a positive and non-positive fit.

FIGS. 16 a-c and 17 a+b show two examples of a toothbrush 50, in whichthe hard component of the entire brush body 50′ and the cup-shapedsegments 20 are injection-molded in one operation. The hard component ofthe entire brush body 50′ is formed, in particular in the head region52, in such a bent manner that bent all-round surfaces 86 are formed,serving as a lateral boundary and anchorage for a membrane 43. “Bent” isunderstood here as also meaning pieces of the all-round surface that runstraight but are arranged at angles to one another (see FIG. 17 a). Inthe case of FIGS. 16 a-c, the hard component is bent in the form of an Sin plan view. The membrane 43 is subdivided into two subregions, whichare respectively located between an arc of the S structure. In the caseof FIGS. 17 a,b, the hard component has a structure in the form of an Hin plan view. The membrane 43 is in turn subdivided into two subregions,which are respectively located—seen in plan view—above and below thelongitudinal axis of the brush. The segments 20 have the form of cupsthat are closed at the bottom and are embedded at their upper peripheryin the membrane 43, which is thin in relation to the depth of the cups(see FIG. 17 b). Brush heads of this type are provided with bristlesconventionally, since the head region 52 provided with the segments 20is integrally formed with the remaining brush body 50′. Carryingstructures such as the S or H form shown may however also be used in thecase of separately produced carrier elements 68, as in FIGS. 11-15.

Carrier elements 68 used as AFT brush heads are generally produced fromthe same hard component as the brush body 50′, in order to ensuresatisfactory welding to the brush handle. Polypropylene (PP) ispreferably used as the hard component. A thermoplastic elastomer (TPE)that bonds, i.e. has an affinity, with PP is preferably used as the softcomponent. This TPE is provided for the creation of flexible regions ofthe AFT head and/or for the forming of rubber-elastic cleaning elements.By means of the AFT method, conventional bristles with a diameter of0.1-0.25 mm are subsequently anchored on the AFT brush head by means ofmelting the bristles on the rear side of the AFT brush head, for exampleas described in EP 1136016. Conventional bristles preferably consist ofa thermoplastic, preferably of polyamide (PA) or polyester (PBT). Thismelting of the bristles produces a melt carpet, which is substantiallyup to 1 mm thick and is somewhat higher at the peripheries as a resultof material displacement. This melt carpet of the material of thebristles is brittle. Moreover, the bristle melt does not bond with thebrush head plate, in the examples shown with the segments 20 arranged,if required, on the carrier element 68, as a result of the melting. Thishas the disadvantage, in particular in the case of flexible mounting ofthe AFT brush head, that the bristle melt may separate itself from theAFT brush head plate, and even break up into individual subregions.

This has a number of negative consequences for the quality of the AFTbrush heads:

a) Water can get into the hollow space through the openings, which maylead to hygiene problems.

b) The load it takes to pull out the bristles and bristle clusters 58 isreduced, since the bristle carpet can break up into small individualregions. If a single part becomes as small as the cross section of acluster, there is no longer any restraining effect.

c) In the case of brush heads with structures that are open at the rear,the bristles can fall out of the head plate to the rear.

To solve these problems, it is proposed to treat the bristles or thebrush head before melting in such a way that adhesion between the AFThead plate and the bristles is produced by the melting during the AFTprocess. In order to achieve this, various possibilities are available:

In a first variant, an additive which brings about adhesion between thematerial of the head plate and the conventional bristles is added to thematerial of the AFT head plate. Here there are so-called adhesionpromoters, which can be admixed during the injection-molding process ofthe AFT head plate or be contained already in the injection-moldinggranules. When the bristles are melted on the rear side of the AFT headplate, the bonding/adhesion of the melt carpet and the bristle plate isthen produced. If soft material is also contained in the AFT bristlehead, as for example in the case of the carrier elements 68 describedabove with a membrane 43, the adhesion promoter may also be admixed withthe soft material. As in the case of the hard material, this adhesionpromoter of course corresponds to the corresponding bristle material.

MATERIAL EXAMPLE 1

polypropylene PP of the head plate contains an additive (adhesionpromoter) for polyamide PA. During the melting of the PA bristles, thebristle melt enters into a bond with the PP of the head plate. Since thebristle handle (bristle body 50′) likewise consists of PP (withoutadhesion promoter), it must be ensured that the welding to the bristlehandle is not adversely influenced by addition of the adhesion promoter.

MATERIAL EXAMPLE 2

polypropylene PP of the head plate contains an additive (adhesionpromoter) for polyester PBT. During the melting of the PBT bristles, thebristle melt enters into a bond with the PP of the head plate. Since thebristle handle (bristle body 50′) likewise consists of PP (withoutadhesion promoter), it must be ensured that the welding to the bristlehandle is not adversely influenced by addition of the adhesion promoter.

Wherever possible, commercially available products, used in particularin the production of composite films or composite tubes, are used as theadhesion promoter. These are for example maleic anhydrides (MSA), EVAC,EBA, SB/PE block copolymer, SB/PP block copolymer, SB blends, etc. Theconcentration is less than 5%, preferably less than 1%.

In order to increase the contact surface between the bristle melt andthe AFT brush head, it is also proposed to provide projections anddepressions in the head plate. However, by contrast with WO 99/11156,these are neither deformed nor incipiently melted. The rear side of thehead plate is preferably roughened, for example with eroded structureshaving a maximum difference in height of 0.5 mm, preferably 0.1 mm. Themethod according to WO 99/11156 has the disadvantage that the melting ofthe plate and bristle material produces a relatively thick melt carpet,which adversely influences the flexibility. Mixing of the materials hasthe effect of producing an undefined material mixture with indefinableproperties.

In a further variant, the adhesion promoter is added to the bristlematerial.

MATERIAL EXAMPLE 3

polypropylene PP of the head plate. During the melting of the polyamidePA bristles, which contain an adhesion promoter for polypropylene PP,the bristle melt enters into a bond with the PP of the head plate.

In a further variant, the head plate is pretreated before the AFTprocess. In the case of polypropylene, the surface tension may bereduced for example by means of a corona flash or flame treatment.

In a further variant, before the AFT process the surface of the headplate is coated or sprayed with an agent which acts for example in themanner of a catalyst during the melting of the bristles, likewise withthe effect of bringing about a bond/adhesion between the head plate andthe bristle melt. This agent may be an adhesive or likewise an adhesionpromoter.

All these variants have the advantage, in particular in the case of AFT,that it is only necessary to pretreat the carrier plate, which onlycomprises a small surface area or a small volume of material. Theremaining part of the toothbrush, in particular the voluminous and heavyhandle, can be produced conventionally. This allows material and time tobe saved.

In particular in the case of brush heads which are open, i.e. on whichthe bristle melt is visible (FIGS. 12-15), it is of advantage tolaminate them, for example by welding on a thin plastic element,applying a film of plastic by means of adhesive attachment or byspraying with paint, lacquer or adhesive resin, by means of a furtherprocess step on the AFT installation and before the welding to the brushhandle (brush body 50′).

This operation can fix the bristle melt to the AFT brush head inaddition to the measures mentioned above. It must be ensured here thatthe welding edges on the AFT brush head plate that are necessary for thewelding to the brush handle are freed.

The above proposals for improved adhesion of the bristle melt areadvantageously used in the case of the carrier elements 68 producedaccording to the invention for the provision of bristles by AFT. Thereis the possibility of likewise adding an adhesion promoter to the softmaterial. However, it is usually adequate to add adhesion promoter tothe hard component. However, the proposals mentioned may also be usedindependently of the production method described above in the case ofother AFT heads or in the case of other methods of providing bristles,such as IMT (EP 0346646) or methods according to EP 1312 281.

FIGS. 18 to 21 show the production of a further toothbrush 50 atdifferent points in time.

As FIG. 18 shows, two parts 116, 118 of the toothbrush 50, to bespecific the toothbrush body 50′ and a toothbrush tongue 88, areproduced in an injection-molding cycle from a first component 38 in thecorresponding hollow regions 12, 14 (cavities) of the first mold 10(compare FIGS. 1-5, 8, 19-21). The hollow regions 12, 14 may, as shownin FIG. 18, be supplied with the liquid polymer material from a gate viaa sprue and runner system. It is also possible to feed each hollowregion 12, 14 via a gate of its own. In the first case, the two parts116, 118 of the toothbrush 50 consist of the same plastic, a hardcomponent, of the same color. In the second case, the two parts 116, 118may consist of different plastics of the same color or different colors,or of the same plastic of different colors.

As revealed in particular by FIG. 19, the one-piece toothbrush body 50′has a handle region 56, a neck region 54 and a head region 52. In theneck region 54 and the head region 52, the toothbrush body has aclearance 90 right through from the upper side to the underside in theform of a spoon. This clearance 90 is surrounded by an all-roundperiphery 52 a, which is integrally formed onto the handle region 56. Inthe head region 52, the periphery 52 a has a series of cup-likedepressions 92, which are open on the upper side, closed on theunderside and are intended for receiving bristle clusters 58. They areproduced in the first injection-molding cycle.

Furthermore, the toothbrush body 50′ has on the upper side in a frontpart of the handle region 56 adjoining the neck region 54 a receivingdepression 94, which is provided with two blind-hole-like positioningholes 96, which are arranged one behind the other on the longitudinalcenter axis of the toothbrush 50.

Seen in plan view, the toothbrush tongue 88 likewise has the shape of aspoon. It is shaped in such a way that it fits in the clearance 90,while leaving a narrow gap 102 between it and the all-round periphery 52a. In the head region 52, the toothbrush tongue 88 is likewise providedwith depressions 92 for receiving bristle clusters 58. In the end regionremote from the head region 52, the toothbrush tongue 88 has aplate-like fastening region 98, which is shaped equally and oppositelyin relation to the receiving depression 94 and is provided withpin-shaped positioning studs 100, which are arranged in a waycorresponding to the positioning holes 96.

In a subsequent method step, the toothbrush body 50′ and the toothbrushtongue 88 are moved in relation to one another (displaced and possiblyrotated), so that the toothbrush tongue 88 comes to lie in the clearance90 and the fastening region 98 comes to lie in the receiving depression94, the positioning studs 100 engaging in the positioning holes 96.

As indicated in FIG. 20, the toothbrush body 50′ and the toothbrushtongue 88 are encapsulated—in a fourth hollow region 48 of a second mold40—with a second component 39, for example a soft component. The secondcomponent 39 reaches in an enveloping manner around the toothbrush body50′ and the toothbrush tongue 88 in the region of the receivingdepression 94 and the fastening region 98, as also shown by FIG. 21. Thetoothbrush tongue 88 is held in the manner of a bending bar that ismounted at one end and can resiliently yield during cleaning of theteeth.

Finally, the periphery 52 a and the toothbrush tongue 88 are providedwith bristles by generally known methods described above.

It is of course also possible to provide or form further regions of thetoothbrush with soft material, as is generally known.

FIGS. 22 to 24 b show parts 116, 118 of a further toothbrush 50. Theproduction of the toothbrush 50 is based on a similar procedure to thatwhich has been described in relation to FIGS. 18 to 21.

FIG. 22 shows, in a way similar to the embodiment that is shown in FIG.19, a first part 116 with an integrated toothbrush tongue 88 in planview. The toothbrush tongue 88 has in turn, seen in plan view, the shapeof a spoon in the head region 52 and in the neck region 54. It is shapedin such a way that it fits in a clearance 90 of a second part 118, shownin FIG. 23, so that essentially there only remains a narrow gap 102between it and the all-round periphery 52 a of the second part 118. Inthe head region 52, the toothbrush tongue 88 is likewise provided inturn with depressions 92 for receiving bristle clusters 58.

In the case of the present embodiment, the first part 116 is producedfrom a first component 58, preferably a hard component, of a firstcolor.

As a difference from the embodiment of the toothbrush tongue 88 that isshown in FIG. 19, the first part 116 of the toothbrush 50 in the presentembodiment does not already end in the front region of the handle region56, but extends further over a significant part of the handle region 56,where it forms the fastening region 98.

In a way similar to the embodiment shown in FIG. 19, FIG. 23 shows asecond part 118 with a likewise spoon-shaped clearance 90 for receivingthe first part 116 in plan view. Like the first part 116, withpreference the second part 118 is integrally designed and likewise has ahandle region 56, a neck region 54 and a head region 52. By contrastwith the embodiment shown in FIG. 19, the second part 118 has in thehead region 52, neck region 54 and in the handle region 56 a clearance90 right through from the upper side to the underside, which is intendedfor receiving the first part 116. The second part 118 accordingly formsa frame, or a toothbrush frame, for the first part 116.

The clearance 90 is bounded in the head region 52 by an all-roundperiphery 52 a, which is integrally formed onto the handle region 56. Inthe head region 52, the periphery 52 a has a series of cup-likedepressions 92, which are open on the upper side, closed on theunderside and intended for receiving bristle clusters 58. They areproduced in the first injection-molding cycle.

The second part 118 is produced with preference in the sameinjection-molding cycle as the first part 116, but in a separate cavity.In a further mold 10′, shown FIG. 25, the second part 118 issimultaneously produced in the same tool (mold 10′) likewise with thefirst component 38, of a first color, preferably a hard component.However, it is also conceivable for the second component 118 to beproduced from a component 38′ that is different from the first component38 and is of the same color as the first component 38 or of a differentcolor. Furthermore, it is conceivable for the component 38′ to consistof the same material as the component 38, but be of a different color.

FIGS. 24 a and 24 b show in plan view and in side view the toothbrush 50not yet provided with bristles, in which the first part 116 from FIG. 22has been inserted into the second part 118 from FIG. 23. The first part116 is fixed with respect to the second part 118 by a second component39, with preference a soft component, partially enclosing the two parts116, 118. The second component 39 is applied in a separate, secondinjection-molding cycle or injection-molding operation. FIG. 24 atherefore shows a second injection point 26 on the rear side of thetoothbrush 50 in the rear handle region 56. The fixing with the secondcomponent 39 in an enveloping manner took place with preference only inthe handle region 56, so that the toothbrush tongue 88 remains free inthe head and neck regions 52, 54. This has the consequence that thetoothbrush tongue 88 of the first part 116 can swing out in thedirection of the upper side and underside of the toothbrush 50 inrelation to the second part 118 thanks to the gap 102. The fixing in thehandle region 56 has the effect that the toothbrush tongue 88 of thefirst part 116 is held in the manner of a bending bar mounted at one endand can resiliently yield during cleaning of the teeth, whereby thetoothbrush 50 becomes compliant and adaptable, in particular in thetwo-part head region 52, whereby particularly gentle teeth cleaning canbe made possible.

In the embodiment shown in FIGS. 24 a and 24 b, the first part 116 andthe second part 118 are only partially enclosed by the second component39, so that certain regions of the first part 116 and/or of the secondpart 118 on the finished toothbrush 50 remain fully or partially visiblefor the customer. For example, indicated in FIG. 22 are a first islandregion 104 and a second island region 106, which remain visible in thejoined-together toothbrush 50 in FIGS. 24 a and 24 b. The second part118 can be seen in FIGS. 24 a and 24 b in the form of an all-roundstrip.

The bristle area is in two parts. A first part of the bristlearrangement is located in the head region 52 of the first part 116,while the second part of the bristle arrangement is arranged in the headregion 52 of the frame-like second part 118.

It is conceivable for the second component 39 to consist of the samematerial as the first component 38, it being possible for it to be ofthe same color as the first component 38 or a different color.

FIGS. 25 and 26 show a tool for the production of the parts 116, 118 ofa further embodiment of the toothbrush 50 that are shown in FIGS. 22 and23.

In a way similar to the multi-part first mold 10 shown in FIGS. 1 to 3,the first mold 10′ that is shown in FIG. 25 also has a first part-mold30, a second part-mold 32 and a third part-mold 34. For this purpose,the first mold 10′ also comprises an index plate 108.

In a way similar to the tool shown in FIG. 8, it is conceivable for theindex plate 108 and the slide 34 to rotate about an axis of rotation D,while the first part-mold 30 and the second part-mold 32 are arranged ina stationary manner.

The mold 10′ shown in FIG. 25 is represented in longitudinal section,the third part-mold 34, in the form of a rib-shaped slide, not beingshown in the sectional representation for the purpose of betterrepresentability. Depressions for forming the first island region 104and the second island region 106 are represented by dashed lines.

On account of the small size of the gap 102 between the toothbrushframe, or the second part 118, and the toothbrush tongue 88, or thefirst part 116, the two parts 116, 118 are produced offset in relationto one another in different separating planes F1, F2 in the first mold10′. FIG. 26 has a cross-sectional representation through the sectionalplane of the first mold 10, shown in FIG. 25, and serves forillustrating the relative offset of the cavities or hollow spaces in theseparating planes F1 and F2.

The production is described below with reference to both FIGS. 25 and26.

The first part-mold 30 is arranged adjoining the second part-mold 32.The first part-mold 30 has on its side facing away from the secondpart-mold 32 a V-shaped recess with two side walls 110 and a U-shapedbottom, which is referred to as wall surface 12 b. The lowermost part ofthe side walls 110 and the bottom of the V-shaped recess are shaped in away corresponding to the upper side of the first part 116 from FIG. 22.

Adjacently adjoining the first part-mold 30 is the index plate 108.Adjacent this index plate 108 is the third part-mold 34, which isreferred to hereafter as slide 34. In this case, the slide 34 passesthrough the index plate 108, which likewise has two widening, slopingside walls 114, which lie in the same planes as the side walls 110, inan upper end position of the slide 34 in such a way that the side wall112 of the slide 34 fits snugly against the side walls 110, 114 of thefirst part-mold 30 and of the index plate 108. In the upper end positionof the slide 34, an end face of the slide 34 forms a wall region 12 aand thereby bounds the first hollow region 12. The wall region 12 a ofthe slide 34 thereby defines a separating plane F1 of the first hollowregion 12. The wall surface 12 a has a shape corresponding to the upperside of the first part 116 that is shown in FIG. 22. The first hollowregion 12 has the shape of the first part 116, which has the toothbrushtongue 88. The slide 34 has on the one hand the inner contour of thesecond part 118 and on the other hand part of the outer contour in theshape of the upper side of the first part 116.

Arranged at the periphery of the first part-mold 30, adjacent the indexplate 108, is a second wall region 14 a. The second separating plane F2is located between the index plate 108 and the first part-mold 30. Thesurface of the index plate 108 in the region opposite the first wallregion 14 a defines a second wall region 14 b. Together with the sidewall 112 of the slide 34, the wall regions 14 a and 14 b bound thesecond hollow region 14. The second hollow region 14 has the shape ofthe second part 118, which forms the toothbrush frame, or the secondpart 118 of the toothbrush 50.

Furthermore, the second part-mold 32 has a first injection point 24.Between the first part-mold 30 and the second part-mold 32, a thirdhollow region 16 is bounded by a wall region 16 a, assigned to thesecond part-mold 32, and a wall region 16 b, assigned to the firstpart-mold 30. This third hollow region 16 has two arms 66, which areconnected to the first hollow region 12, or the second hollow region 14,via a through-opening 28. The third hollow region 16 defines the sprueand runner system. In the case of the parts 116, 118 produced by thefirst mold 10′, represented in FIG. 25, the injection pointsrespectively lie on the rear side (with respect to the finishedtoothbrush 50) of the two plastic parts 116, 118 in the lower end regionof the handle region 56.

In the first injection-molding cycle, shown in FIGS. 25 and 26, theslide 34 is in the upper end position. In the first injection-moldingcycle, a first component 38, comprising liquid polymer material, isinjected via the first injection point 24 into the third hollow region16 and via the arms 66 respectively into the first and second hollowregions 12, 14. Therefore, the first part 116 and the second part 118are simultaneously injection-molded in a single injection-moldingoperation. In this case, the two parts 116, 118 of the toothbrush 50consist of the same polymer, preferably a hard component of one color orcolorless.

It is also possible to feed each hollow region 12, 14 via a respectivegate of its own. In this case, the two parts 116, 118 may be producedfrom different polymers of the same color or different colors, or fromthe same polymer of different colors.

In a subsequent method step, the second part-mold 32 is removed from thefirst part-mold 30, whereby the sprue and runner system of solidifiedmaterial 22 is exposed and is removed in a way similar to the methodpreviously mentioned.

In a further method step, the slide 34 is brought into the lower endposition, so that the wall surface 12 a is displaced from the firstseparating plane F1 in such a way in the direction of arrow P that thatit comes to lie in the second separating plane F2, which issubstantially flush with the wall surface 14 b of the index plate 108.Consequently, the slide 34 brings the first part 116 with the tonguebody 88 into a second position for a second injection-molding cycle, inwhich the first part 116 with the tongue body 88 must be located withinthe second part 118 (the toothbrush frame).

The first part-mold 30 with the second part-mold 32 is subsequentlyremoved from the slide 34 and the index plate 108, the two finishedparts 116, 118 being held in a front region of the index plate 108.After that, the index plate 108 and the slide 34 inserted into it aretogether rotated away about an axis of rotation D—in a way similar tothe tool shown in FIG. 8. As a result, the first part 116, pushed intothe second part 118, is moved into a further hollow region, or a new,further part-mold 46 (not shown). The movement is initiated by the indexplate 108. During this rotational movement, the two parts 116, 118 areheld in a front region of the index plate 108.

In the second injection-molding cycle, the first part 116 (having thetongue body 88) is connected to the second part 118 (forming thetoothbrush frame), displaced in one another, in that, in the state inwhich they are pushed one into the other, they are encapsulated in anenveloping manner, or partially encapsulated in an enveloping manner,preferably only in the handle region 56 with a plastic of a second (orthird) component 39. With preference, the encapsulation takes place inthis case with a soft component.

After the shaping, the periphery 52 a of the second part 118 and thetoothbrush tongue 88 of the first part 116 are provided with bristles bygenerally known methods described above, after which the productionprocess of the toothbrush 50 is complete.

The three parts, or the first two parts 116, 118 and the encapsulation,can therefore consequently be produced from three different components38, 38′, 39. That is to say that a combination of hard and/or softcomponents can be realized. For example, the first two parts 116, 118may be produced from a hard component, while the encapsulation takesplace with a soft component. By variation of the components and the typeof injection (separate gates or sprue and runner system), it is alsopossible for a wide variety of color combinations to be realized.

It is of course also possible to provide further regions of thetoothbrush 50 with soft material or form them with it, as is generallyknown.

It is also conceivable for the neck region 54 to be encapsulated withthe second component 39, in an embodiment not shown. This results in asmaller deflection in comparison with the embodiment above.

However, it is also conceivable for the fastening region 98 to extendfrom the first part 116 and the corresponding clearance 90 in the secondpart 118 to extend only over part of the handle region 56, for exampleonly over half or only over a third, of the length of the handle region56 (seen from the front end region, adjoining the neck region 54).

1. A method for producing a toothbrush with a body which comprises atleast a handle region, a neck region and a head region and a carrierelement connected to the body, with the following steps: producing aplurality of segments in a form of sleeves or cups as well as otherregions of the carrier element of a first component in a first step;producing connecting elements in a form of a membrane by injection of asecond component in a further step, said connecting elements connectingthe segments and the other regions of the carrier element; thereafterfitting the carrier element with bristles; and connecting the carrierelement including the bristles to a separately produced body.
 2. Themethod as claimed in claim 1, wherein the segments are molded into anelliptical or kidney shaped form or in the form of a figure of eight. 3.The method as claimed in claim 1, wherein the head region has an edgeonto which an outer edge of the carrier element comes to bear wherebythe carrier element and the brush body will be connected undetachablyalong a line.
 4. The method as claimed in claim 3, wherein the headregion and the carrier element are welded along said line producing awelding area, said welding area being partially disrupted by openings ordifferent material components.
 5. The method as claimed in claim 1,wherein the carrier element is connected to the head region of the bodyunder prestress in such a way that it is made to arch up.
 6. The methodas claimed in claim 1, wherein the first component is a hard componentand the second component is a hard or a soft component.
 7. The method asclaimed in claim 6, wherein the hard component comprises at least one ofof styrene-acrylonitrile (SAN), polyethylene terephthalate (PET),polyethylene (PE), polymethylmethacrylate (PMMA), acrylobutadienestyrene (ABS) and polypropylene (PP).
 8. The method as claimed in claim6, wherein the soft-component consists of a rubber-elastic material. 9.The method as claimed in claim 1, wherein a spatial position of thesegments in relation to at least one of one another and the otherregions is changed before the injection-molding of the second component.10. The method as claimed in claim 1, the fitting the carrier elementwith bristles further comprises: leading a bristle cluster through anopening in the carrier element; and then melting the bristle cluster atthe rear end to connect the bristle cluster to the carrier element. 11.The method as claimed in claim 10, wherein the bristle cluster is ledthrough an opening of a segment.
 12. The method as claimed in claim 1,wherein cleaning and massaging elements are formed by the secondcomponent.
 13. Toothbrush with a body comprising at least a handleregion, a neck region and a head region, wherein the body at leastpartially comprises a first and a second component, and a carrierelement comprising a plurality of segments and other regions of a firstcomponent and a membrane of the second component connecting the segmentsand the other regions, wherein the head region is connected to otherregions of the first component of the carrier element and the carrierelement holds bristles.
 14. Toothbrush as claimed in claim 13, whereinthe other regions of the first component form an elliptical closedperiphery onto which sleeves are directly molded, in the head region acircular edge is formed against which an outer edge of the carrierelement bears, and, along a line formed by the edge and the outer edge,the carrier element is undetachably connected to the body. 15.Toothbrush as claimed in claim 13, wherein the other regions of thefirst component form two material pieces, the head region has two edgesrunning in a transverse direction and serving as anchoring locations forthe carrier element and the two material pieces are fastened to the twoedges, respectively.
 16. Toothbrush as claimed in claim 13, wherein thebody is (1) bent in the head region, and (2) branched one or more timestoward a front end to form a skeletal carrying structure with ananchoring location formed at an end of each branch, a further anchoringlocation is built on the body in the form of an elongate edge at atransition from the head region to the neck region, the carrier elementhas an elongate material piece at one end and plate-like pieces that aredistributed in a manner to correspond to at least one anchoringlocation, the membrane is located between the olongate material pieceand the plate-like material pieces, and the elongate material piece andthe plate-like material pieces form the other regions of the firstcomponent.
 17. Toothbrush as claimed in claim 13, wherein the segmentshave a form of at least one of singular and interconnected sleeves orcups, which are adapted to receive bristle clusters.
 18. Toothbrush asclaimed in claim 17, wherein the segments have an opening,the openinghaving a shape that is at least one of elliptical, circular,kidneyshaped and in the form of a figure eight.
 19. Toothbrush as claimed inclaim 13, further comprising at least one of cleaning and massagingelements of the second component.
 20. A device for carrying out themethod as claimed in claim 1, the device comprising: a first moldincluding: first hollow regions, which correspond to the other regionsto be produced from the first component and to which the first componentcan be supplied, second hollow regions, which are arranged at a distancefrom one another and correspond to the segments to be produced from thefirst component, and at least one third hollow region, to which thefirst component can be supplied and which is connected with the secondhollow regions in such a way that material supplied to the at least onethird hollow region is supplied to the second hollow regions, whereinthe second hollow regions for producing a plurality of segments that areseparate from one another comprise a plurality of subregions, which arein connection with one another exclusively via the at least one thirdhollow region; a second mold, including: a fourth hollow region which islarger than the second hollow regions, at least in the region around thesegments, wherein the second mold is shaped such that it is adapted tothe first mold in such a way that connecting elements are formed fromthe second component as a membrane, in which the segments are at leastpartially embedded and which is resiliently connected to the otherregions of the first component; and means for removing the first mold atleast partially in such a way that the at least one third hollow region,including solidified material remaining in the at least one third hollowregion, is removed from the segments and the other regions of thetoothbrush.
 21. A device as claimed in claim 20, further comprisingmeans for introducing the segments and the other regions into the secondmold.
 22. A device as claimed in claim 20, wherein the second hollowregions are shaped in such a way that the segments have the form ofsleeves that are open at two ends, through which bristles can be led,the opening directions being oriented substantially perpendicularly inrelation to a surface area of the head region.
 23. A device as claimedin claim 20, wherein the first mold comprises at least three part-molds,the first and second hollow regions being formed between a firstpart-mold and a second part-mold and the at least one third hollowregion being formed between the second part-mold and a third part-mold.24. A device as claimed in claim 20, further comprising a handling unitfor changing at least one of a position and an orientation of thesegments in relation to one another before the second component isinjected.
 25. The method as claimed in claim 8, wherein therubber-elastic material is a thermoplastic elastomer (TPE).
 26. Themethod as claimed in claim 25, wherein the thermoplastic elastomer ispolyurethane (PUR).
 27. The method as claimed in claim 9, wherein thespatial position of the segments is changed through at least one oftranslation and rotation.
 28. The method as claimed in claim 12, whereinthe cleaning and massaging elements are connected to the membrane. 29.The method as claimed in claim 28, wherein the cleaning and massagingelements are produced in a same production step as the membrane. 30.Toothbrush as claimed in claim 14, wherein the carrier element isconnected to the body by welding.
 31. Toothbrush as claimed in claim 15,wherein the two material pieces are fastened to the two edges bywelding.
 32. Toothbrush as claimed in claim 19, wherein the cleaning andmassaging elements are connected to the membrane.
 33. Toothbrush asclaimed in claim 32, wherein the cleaning and massaging elements areproduced in a same production step as the membrane.